Shaft assemblies, such as plunger assemblies, are widely used in valve or pump systems. Shafts or plungers in these systems can be moved reciprocally. It is important to properly seal the shaft or plunger assemblies to have satisfactory performance without excessive leakage.
Conventionally, the shaft or plunger assemblies can be sealed by cone packing components or materials. As shown in FIG. 1, a plunger assembly 100 includes a housing 101, a cap 102, a plunger 103, and four cone packing components 104a, 104b, 104c, and 104d. The plunger 103 is positioned within the housing 101. The cone packing components 104a-d are positioned to surround the plunger 103. With the assistance provided by the cone packing components 104a-d, the cap 102 and the housing 101 are designed to form an leak resistant chamber 105 for the plunger assembly 100 to function properly. As shown in FIG. 2, the plunger 103 can be configured to move reciprocally along a central axis (indicated as an arrow A) of the housing 101. However, during operation, the cone packing components 104a-d can be extruded outside the leak resistant chamber 105 (i.e., forming an extrusion 201) due to the movement of the plunger 103, as illustrated in FIG. 2. The extrusion 201 may cause malfunction of the plunger assembly 100, which may include increased leakage through a leak path. Therefore, an improved sealing system or method is desirable.